Hysteretic spin crossover in iron(<scp>ii</scp>) complexes of a new pyridine–triazole–pyrazine ligand is tuned by choice of NCE co-ligand

Hogue, Ross W.; Miller, Reece G.; White, Nicholas G.; Feltham, Humphrey L. C.; Jameson, Guy N. L.; Brooker, Sally

doi:10.1039/c3cc43922d

Cited by 33 publications

(38 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…respectively, consistent with high spin S = 2 iron(II) complexes. Some iron(II) compounds containing 2-pyridyl-1,2,3-triazole ligands are reported to be low spin [40] and other high spin at room temperature, and some exhibit spin crossover properties [41]. For example, certain iron(II) complexes with ferrocene-containing triazole-pyridine ligands, trans-[Fe(Fctzpy)2(NCX)2]•CHCl3 (Fc-tzpy = 4-(2-pyridyl)-1H-1,2,3-triazol-1-ylferrocene, X = S (1) and X = Se (2)) exhibit spin crossover display thermal-and light-induced spin crossover properties.…”

Section: Characterisation Of the Fe-ligand Complexesmentioning

confidence: 99%

Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R = CH3, OCH3, COOH, F, Cl, CN, H and CF3

Conradie

Mtshali

et al. 2019

Inorganica Chimica Acta

View full text Add to dashboard Cite

Eight different Dichloro(bis{2-[1-(4-R-phenyl)-1H-1,2,3-triazol-4-yl-N 3 ]pyridine-N})iron(II) compounds, 2 -9, have been synthesised and characterised, where group R = CH3 (L 2 ), OCH3 (L 3 ), COOH (L 4 ), F (L 5 ), Cl (L 6 ), CN (L 7 ), H (L 8 ) and CF3 (L 9 ). The single crystal X-ray structure was determined for the L 3 which was complemented with Density Functional Theory calculations for all complexes. The structure exhibits a distorted octahedral geometry, with the two triazole ligands coordinated to the iron centre positioned in the equatorial plane and the two chloro atoms in the axial positions. The values of the Fe II/III redox couple, observed at ca. -0.3 V versus Fc/Fc + for complexes 2 -9, varied over a very small potential range of 0.05 V. The observation that the different R substituents have virtually no effect on the values of the Fe II/III redox couple for all eight complexes 2 -9, is explained by the character of the highest molecular orbitals of complexes 2 -9, which do not show any communication of electron density between the various ligands and the metal Fe. However, the HOMOs of the free ligands L 2 -L 9 , display extended -character over the entire ligand, explaining the sensitivity of the 1 H NMR C-H-triazole peak, which is dependent on the electron donating/withdrawing power of the R substituent attached to the 2-[1-(4-R-phenyl)-1H-1,2,3-triazol-4-yl]pyridine ligands. Keywords(1,2,3-triazol-4-yl)pyridine; redox potential; iron; DFT TOC graphics and textFe II/III redox couple of Fe- (1,2,3-triazol-4-yl)pyridine complexes, observed at ca. -0.3 V vs. the Fe II/III redox couple of ferrocene. Highlights Fe-(1,2,3-triazol-4-yl)pyridine complexes demonstrate intermolecular H bonding in the solid state Fe-(1,2,3-triazol-4-yl)pyridine complexes display π…π stacking in the solid state Fe II/III redox couple is observed at ca. -0.3 V vs. the Fe II/III redox couple of ferrocene. DFT calculations show that Fe-(1,2,3-triazol-4-yl)pyridine is high spin

show abstract

Section: Characterisation Of the Fe-ligand Complexesmentioning

confidence: 99%

Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R = CH3, OCH3, COOH, F, Cl, CN, H and CF3

Conradie

Mtshali

et al. 2019

Inorganica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…Interestingly, the magnetic profile is stable and repeatable over multiple cycles, and it is independent of scan rate, which is akin to recent data for mononuclear Fe(II) SCO complexes also showing small hysteresis but with more abrupt transitions. 12 To the best of our knowledge, this is the first Fe(III) complex a dmit = 1,3-dithia-2-thione-4,5-dithiolato. a dmit = 1,3-dithia-2-thione-4,5-dithiolato.…”

mentioning

confidence: 90%

Ligand effects in a heteroleptic bis-tridentate iron(iii) spin crossover complex showing a very high T_1/2 value

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Existing bis-terdentate triazole ligands PMRT and thioether analogues PRST , and potentially bis-bidentate Rdpt ligands , ( R = amino, methyl, phenyl, tolyl, hexadecyl, etc. ; ,,,,− R′ = pyrazinyl, , pyridazinyl, phenyl, quinolinyl, etc. ), ,,, as well as the nonsymmetrically functionalized RR′pt -type ( L pz and L pdz ) , and RR′pht -type ( L pyridazine , L pyridine , and L pyrazine ) ,, ligands, which have produced many SCO-active iron(II) materials.…”

Section: Introductionmentioning

confidence: 99%

Solvent Polarity Predictably Tunes Spin Crossover T_1/2 in Isomeric Iron(II) Pyrimidine Triazoles

et al. 2018

Self Cite

View full text Add to dashboard Cite

Two isomeric pyrimidine-based Rdpt-type triazole ligands were made: 4-(4-methylphenyl)-3-(2-pyrimidyl)-5-phenyl-4 H-1,2,4-triazole (L) and 4-(4-methylphenyl)-3-(4-pyrimidyl)-5-phenyl-4 H-1,2,4-triazole (L). When reacted with [Fe(pyridine)(NCE)], where E = S, Se, or BH, two families of mononuclear iron(II) complexes are obtained, including six solvatomorphs, giving a total of 12 compounds: [Fe(L)(NCS)] (1), [Fe(L)(NCSe)] (2), 2·1.5HO, [Fe(L)(NCBH)]·2CHCl (3·2CHCl), 3 and 3·2HO, [Fe(L)(NCS)] (4), 4·HO, [Fe(L)(NCSe)] (5), 5·2CHOH, 5·1.5HO, and [Fe(L)(NCBH)]·2.5HO (6·2.5HO). Single-crystal X-ray diffraction reveals that the N-coordinated iron(II) centers in 1, 2, 3·2CHCl, 4, 5, and 5·2CHOH have two bidentate triazole ligands equatorially bound and two axial NCE co-ligands trans-coordinated. All structures are high spin (HS) at 100 K, except 3·2CHCl, which is low spin (LS). Solid-state magnetic measurements show that only 3·2CHCl ( T above 400 K) and 5·1.5HO ( T = 110 K) undergo spin crossover (SCO); the others remain HS at 300-50 K. When 3·2CHCl is heated at 400 K it desorbs CHCl becoming 3, which remains HS at 400-50 K. UV-Vis studies in CHCl, CHCl, (CH)CO, CHCN, and CHNO solutions for the BH analogues 3 and 6 led to a 6:1 ratio of L /Fe(II) being employed for the solution studies. These revealed SCO activity in all five solvents, with T values for the 2-pyrimidine complex (247-396 K) that were consistently higher than for the 4-pyrimidine complex (216-367 K), regardless of solvent choice, consistent with the 2-pyrimidine ring providing a stronger ligand field than the 4-pyrimidine ring. Strong correlations of solvent polarity index with the T values in those solvents are observed for each complex, enabling predictable T tuning by up to 150 K. While this correlation is tantalizing, here it may also be reflecting solvent-dependent speciation-so future tests of this concept should employ more stable complexes. Differences between solid-state (ligand field; crystal packing; solvent content) and solution (ligand field; solvation; speciation) effects on SCO are highlighted.

show abstract

Hysteretic spin crossover in iron(ii) complexes of a new pyridine–triazole–pyrazine ligand is tuned by choice of NCE co-ligand

Cited by 33 publications

References 32 publications

Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R = CH3, OCH3, COOH, F, Cl, CN, H and CF3

Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R = CH3, OCH3, COOH, F, Cl, CN, H and CF3

Ligand effects in a heteroleptic bis-tridentate iron(iii) spin crossover complex showing a very high T_1/2 value

Solvent Polarity Predictably Tunes Spin Crossover T_1/2 in Isomeric Iron(II) Pyrimidine Triazoles

Contact Info

Product

Resources

About

Hysteretic spin crossover in iron(ii) complexes of a new pyridine–triazole–pyrazine ligand is tuned by choice of NCE co-ligand

Cited by 33 publications

References 32 publications

Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R = CH3, OCH3, COOH, F, Cl, CN, H and CF3

Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R = CH3, OCH3, COOH, F, Cl, CN, H and CF3

Ligand effects in a heteroleptic bis-tridentate iron(iii) spin crossover complex showing a very high T1/2 value

Solvent Polarity Predictably Tunes Spin Crossover T1/2 in Isomeric Iron(II) Pyrimidine Triazoles

Contact Info

Product

Resources

About

Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R = CH3, OCH3, COOH, F, Cl, CN, H and CF3

Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R = CH3, OCH3, COOH, F, Cl, CN, H and CF3

Ligand effects in a heteroleptic bis-tridentate iron(iii) spin crossover complex showing a very high T_1/2 value

Solvent Polarity Predictably Tunes Spin Crossover T_1/2 in Isomeric Iron(II) Pyrimidine Triazoles